Back to basics...

Meeting with the microbes

Part 5



Well hello there! Welcome back to the fifth part of our Meeting with the Microbes series: This month’s exclusive “autobacteriography” is with Mr. Bacillus cereus.

Brace yourself................you are becoming microscopic............
Honey, I shrunk the readers begins!!

PART 5: Bacillis (B.) cereus


The Food Safety Network (TFSN) Reporter: You can’t B. cereus...ha ha ha just joking...I love that micro joke. Welcome Mr. Bacillus cereus (B.cereus), to The Food Safety Network. We are most fortunate to have you here, live and exclusive on our website.



Mr. B. cereus: Thank you. Yes I get that often among some of my friends...good to be here on your show and to share myself with all your viewers!



TFSN Reporter: Well please don't share too much, remember you are a pathogen and these are humans after all! Let’s cut to the chase. Tell me about yourself.



Mr. B. cereus: Ha ha ha...I am a gram-positive, rod-shaped spore-former that likes the air around me, but I can survive under anaerobic conditions too.

 

TFSN Reporter: What do you mean...you can survive without oxygen?

 

Mr. B. cereus: As I said, I prefer the presence of oxygen to grow but can survive and grow quite easily if no oxygen is present...so you can’t kill me by depriving me of oxygen!

 

TFSN Reporter: You are not cereus (ha, ha, ha)?  Tell me more about your spores.

 

Mr. B. cereus: Yes, about my spores, or my survival kit for a better use of words.  If I am place under conditions not favourable to my growth, for example, low pH, high temperature or another hurdle you may place in my growth path, I am able to become dormant and survive in the product as a highly-resistant spore.  Once the growth conditions become favourable again, I will germinate from the spore into a vegetative cell and proliferate and grow in the food.

 

TFSN Reporter: Wow, it’s like your armour tank in a war zone?

 

Mr. B. cereus: Yes, the best defence mechanism ever...but not indestructible – the autoclave is my sworn enemy!

 

TFSN Reporter: Mmmm...information you should not be sharing with our audience (who are food producers)! But you are not as cereus as some of your pathogenic friends?

 

Mr. B. cereus: That’s true! I am only responsible for a minority of foodborne illnesses (2-5%), causing severe nausea, vomiting and diarrhoea.

 

TFSN Reporter: I was actually one of the 2-5% statistic...and was initially diagnosed as having Clostridium perfringens food poisoning?

 

Mr. B. cereus: MMmmmm, so true, I have heard this before and it is because I mimic the symptoms of my pathogenic friend.

 

TFSN Reporter: Tell us more...all the details...

 

Mr. B. cereus: Your mind is sick!  I generally cause illness due to the survival of my spores in food that is improperly cooked. Cooking temperatures of less than or equal to 100°C allows a few of my spores to survive.

 

TFSN Reporter: (Interrupting)...but refrigeration should then assist with keeping you at bay?

 

Mr. B. cereus: Yes, but often improper refrigeration found to be the root cause of most foodborne outbreaks...and improper refrigeration allows my spores to germinate!

 

TFSN Reporter: So what precautions should our viewers then take to keep you under control in their food/factories?

 

Mr. B. cereus: Cooked foods that you are not immediately going to eat or rapidly cool and refrigerate, should be kept at temperatures above 60°C.  I love temperatures between 10-50°C and it is at these temperatures that my spores will germinate.

 

TFSN Reporter: But is it not the enterotoxins that you produce that make us ill?  So if you grow, you produce enterotoxins?

 

Mr. B. cereus: You are quite clued up! Yes, my growth results in production of enterotoxins.  But I need to present in large numbers 

 

TFSN Reporter: What does this enterotoxin of yours do?

 

Mr. B. cereus: My enterotoxin, which is highly resistant to heat and pH between 2 and 11, if ingested results in two types of illness.

 

TFSN Reporter: One being the diarrhoea, which I was blessed with, and the other?

 

Mr. B. cereus: Ha ha ha yes, sorry I know it’s not a laughing matter, the other one is emetic (vomiting) syndrome.  The diarrheal type is associated with a number of foods and has an 8-16 hour incubation time resulting in diarrhoea, abdominal cramps and pain.  The emetic type is commonly associated with infected rice that was not cooked for a time and temperature sufficient to kills any of the spores present.  Then as always, refrigeration was improper and I was able to produce a toxin, cereulide, which is not inactivated by later heating.  Nausea and vomiting thus set in quickly (1-5 hours after consumption).

 

TFSN Reporter: Wow, I am grateful not to have had that version of your wrath...but I was very ill anyway! So we must cook rice very well and keep refrigeration under strict control, but what other foods do you like inhabiting?

 

Mr. B. cereus: I am a lover of many foods - meats, milk, vegetables and fish! These normally give rize to my brothers that are associated with the diarrheal type of food poisoning.  The more starchy food-types, mainly rice, but also potato, pasta and cheeses have been implicated in the emetic outbreaks.

 

TFSN Reporter: That would explain your fatter rod shape compared to some of your other species – your love for carbohydrates has favoured your shape!

 

Mr. B. cereus: Ha, ha...you are perceptive. And because people love starchy carbs too, makes my entry and survival into the human body so much easier!

 

TFSN Reporter: Talking about people, do you prefer young, old, immune-suppressed? Who are your favourite?

 

Mr. B. cereus: I am not picky and love all ages, sizes and types – but especially those who love STARCHY CARBS!! Ha ha ha...

 

TFSN Reporter: So there goes my Italian girlfriend, dumped and no more carbs for me!

 

Well on that starchy note, our very cereus autobacteriography (with Mr Bacillus cereus) and part five of our Meeting with microbes Series draws to a close.

Brace yourself..... you are becoming macroscopic..... Honey, I shrunk the readers ends!


Remember small steps and you will...
Let’s rephrase that...you are MAKING (more) SENSE OUT OF MICRO....

 

 

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